Screen



Feb. 11, 1930. F. c. MORROW SCREEN Filed Nov. 14, 1928 ll ll.

I CCMafiraw Patented Feb. 11, 1930 UNITED STATES FRANlK C. MORROW, OF WELLSTON, OHIO SCREEN Application filed November 14, 1928. Serial No. 319,289.

This invention relates to perforated metal screens such as used for sizing and preparing coal, sand, gravel, stone, etc.

Heretofore the best results have been ohtained by utilizing stepped screens. These have been made by producing transverse offsets or steps in sheet metal, there being openings provided in the successive steps by cut ting the metal from the plates. Screens of this type, however, have been objectionable for several reasons. As they have been formed of sheet metal, the metal being of uniform thickness or gage, the screens have quickly worn through at the bends along the tops of the shoulders between the steps, this wear being accelerated because of the fact that the bending operation itself tends to weaken the plate at these points where they are subjected to the greatest wearing action.

It has furthermore been necessary to reinforce perforated plates by arranging channel strips or the like thereunder for the purpose of preventing sagging.

It is an object of the present invention to provide a perforated metal screen which does not require separate reinforcing means, can be produced from standard sizes of stock material, and has its greatest strength at those points subjected to the greatest wear.

A further object is to provide a perforated metal screen utilizing angular shoulders instead of rounded shoulders such as have been used heretofore, thereby permitting the use of perforations more closely approximating round perforations than has heretofore been possible, these perforations and the angular shoulders cooperating to prevent long nar row slabs or strips of material from passing through the apertures or perforations because they cannot gradually tilt and slide downwardly 0d of the shoulders as in structures where inclined or rounded steps are employed.

l vith the foregoing and other objects in view-which will appear as the description proceeds the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the'invention.

In the accompanying drawings the preferred form of the invention has been shown.

In said drawings,

Figure 1 is a plan view of a portion of a metal screen constructed in accordance with the present invention.

Figure 2 is a section on line 22, Figure 1.

Figure 3 is a front elevation of a portion of the screen.

Referring to the figures by characters of reference, 1 designates inverted channeled metal strips that can be of standard size produced in the usual way. Openings 2 are formed in each of these strips, each opening extending through the web 3 and one of the flanges 4 of the strip thereby to form depending fingers 4-. The several strips constituting the screen are assembled in stepped relation, the meeting flanges of the strips being held together by welding as shown at 5. The openings in each strip are staggered relative to the openings in the next adjoining strip and while the openings can be made of any desired shape, it is preferred to form them as shown in Figure 1 wherein each opening extends only partly across the web 3 and has its exposed end portion substantially semicircular, the straight sides of the opening being parallel and extended downwardly within the flange portion.

As each strip 3 is formed of a channeled member of standard shape, the thickness of the member at the angle will be greater than at other points, this being clearly indicated at 6. As the greatest wear on each strip occurs at this angle 6 it will be apparent that by providing more metal at this point the life of the screen will be greatly prolonged.

Another advantage resulting from the use of channeled strips in the formation of a screen resides in the fact that each step produced is angular. Therefore, whenever any long slabs of material ride over a step they will not be inclined prematurely and enter into an opening in the next step, as would be the case should the step or shoulder be inclined or rounded. Consequently the danger of material becoming lodged in the openings is reduced to the minimum.

As the screen is formed of channeled strips, the flanges of the strips constitute transverse reinforcements so that it does not become necessary to provide supplemental reinforcing means under the screens in order to prevent sagging. Instead the screens can be made of proper size and then lowered to position in a supporting frame where it may be secured by any suitable means. The lowermost step of the screen can of course be provided with a cross strip 7 welded to the flange 4 of the step so as to bridge the lowerportions of the openings 2 as shown at the left of Figures 1 and 2 and at the bottom ofFi-gure 3.

What is claimed is:

1. A screen comprising a plurality of perforated channeled strips disposed in stepped relation and contacting along their sides, said strips being connected at their meeting sides by welding.

2. A perforated metal screen comprising channeled strips disposed in stepped relation and contactingalong their longitudinal edges, said strips being joined by welding.

3. A perforated metal screen comprising strips each having parallel longitudinal flanges, said strips being disposed in stepped relation and having said flanges contacting and joined by welding, one of the flanges of each strip constituting a depending reinforcement extending transversely of the screen.

4:. A perforated metal screen comprising strips each liqving spaced longitudinal flanges, said strips being-disposed instepped relation and having the flanges ofeachstrip contacting with and joined by welding to the adjacent flanges of the next adjoining strips, one flange of each strip constituting a depending reinforcement extending transversely of the screen, there being openings in the other flange of each strip, said openings extending into the strip between the flanges.

In testimony that I claim the foregoing as my own, I have hereto affixed my signature.

FRANK C. 'MORROW. 

